Caveolin-1 is down-regulated in alveolar rhabdomyosarcomas and negatively regulates tumor growth

Targeting DNA Methylation Machinery in Pediatric Solid Tumors

DNA methylation is a key epigenetic regulatory mechanism that plays a critical role in a variety of cellular processes, including the regulation of cell fate during development, maintenance of cell identity, and genome stability. DNA methylation is tightly regulated by enzymatic reactions and its deregulation plays an important role in the development of cancer. Specific DNA methylation alterations have been found in pediatric solid tumors, providing new insights into the development of these tumors. In addition, DNA methylation profiles have greatly contributed to tune the diagnosis of pediatric solid tumors and to define subgroups of patients with different risks of progression, leading to the reduction in unwanted toxicity and the improvement of treatment efficacy. This review highlights the dysregulated DNA methylome in pediatric solid tumors and how this information provides promising targets for epigenetic therapies, particularly inhibitors of DNMT enzymes (DNMTis). Opportunities and limitations are considered, including the ability of DNMTis to induce viral mimicry and immune signaling by tumors. Besides intrinsic action against cancer cells, DNMTis have the potential to sensitize immune-cold tumors to immunotherapies and may represent a remarkable option to improve the treatment of challenging pediatric solid tumors.

Caveolin-1 expression predicts favourable outcome and correlates with PDGFRA mutations in gastrointestinal stromal tumours (GISTs)

AIMS

Novel prognostic markers are warranted for gastrointestinal stromal tumours. Caveolin-1 is a multifunctional protein that proved to be associated with outcome in multiple tumour types. Aim of this study was to investigate Caveolin-1 expression and prognostic efficacy in a series of gastrointestinal stromal tumours.

METHODS

Caveolin-1 expression was assessed by immunohistochemistry in a retrospective series of 66 gastrointestinal stromal tumours representative of the different molecular subtypes. Correlations with clinical, histopathological and molecular features were investigated. Statistical analyses were performed as appropriate.

RESULTS

Thirty-five cases out of 66 (53.0%) expressed Caveolin-1. Presence of Caveolin-1 expression correlated with favourable histopathologic and clinical traits, including a lower mitotic count (p=0.003) and lower relapse rate (p=0.005). Caveolin-1 expression also resulted associated with the presence of PDGFRA mutations (p=0.010). Outcome analyses showed a favourable prognostic significance of Caveolin-1 expression in terms of relapse-free survival (HR=0.14; 95% CI=0.03 to 0.63) and overall survival (HR=0.29; 95% CI=0.11 to 0.74), even after adjusting for the mutational subgroup (relapse-free survival: HR=0.14, 95% CI=0.04 to 0.44; overall survival: HR=0.29, 95% CI=0.11 to 0.51) and imatinib treatment (relapse-free survival: HR=0.14, 95% CI=0.02 to 0.81; overall survival: HR=0.29, 95% CI=0.17 to 0.48).

CONCLUSION

Caveolin-1 represents a novel prognostic marker in gastrointestinal stromal tumours. Further studies are warranted to validate these results and to explore the mechanisms linking Caveolin-1 expression with the PDGFRA oncogenic pathway.

Increased ERK phosphorylation and caveolin-1 expression on K562 human chronic myelogenous leukemia cells by jacalin, a dietary plant lectin

The potential antitumor effects of jacalin, the plant lectin that specifically recognizes the tumor-associated Thomsen-Friedenreich antigen has been extensively studied. We had earlier reported jacalin to be mitogenic to K562, the Bcr-Abl expressing erythroleukemia cell line. The dearth of studies highlighting the proliferative effects of jacalin and other lectins motivated us to unveil the mechanism underlying the mitogenic effects of jacalin. Caveolin-1 (cav-1) is an integral membrane protein, known to play a crucial role in cell signaling, lipid transport, and membrane trafficking. The role of cav-1 in tumorigenesis is considered to be controversial as it can suppress as well as promote tumor growth, depending on the cellular context. In the present study, we propose that cav-1 plays the central role in the mitogenic effects of jacalin on the K562 cells. In accordance, the mRNA, as well as protein expression of cav-1 was found to be upregulated in the jacalin-treated K562 cells as compared to the untreated control. Further, jacalin stimulation also increased the phosphorylation of ERK and Akt. The rationale that leads to the initial conjecture about cav-1 was that the sequence of jacalin possesses a cav-1-binding site.

Caveolin-1 function at the plasma membrane and in intracellular compartments in cancer

Caveolin-1 (CAV1) is commonly considered to function as a cell surface protein, for instance in the genesis of caveolae. Nonetheless, it is also present in many intracellular organelles and compartments. The contributions of these intracellular pools to CAV1 function are generally less well understood, and this is also the case in the context of cancer. This review will summarize literature available on the role of CAV1 in cancer, highlighting particularly our understanding of the canonical (CAV1 in the plasma membrane) and non-canonical pathways (CAV1 in organelles and exosomes) linked to the dual role of the protein as a tumor suppressor and promoter of metastasis. With this in mind, we will focus on recently emerging concepts linking CAV1 function to the regulation of intracellular organelle communication within the same cell where CAV1 is expressed. However, we now know that CAV1 can be released from cells in exosomes and generate systemic effects. Thus, we will also elaborate on how CAV1 participates in intracellular communication between organelles as well as signaling between cells (non-canonical pathways) in cancer.

Novel insights into the evolution of the caveolin superfamily and mechanisms of antiapoptotic effects and cell proliferation in lamprey

Caveolin-1 is the main structural and functional component of caveolin, and it is involved in the regulation of cholesterol transport, endocytosis, and signal transduction. Moreover, changes in caveolin-1 play an important role in tumorigenesis and inflammatory processes. Previous studies have demonstrated that human caveolin-1 is mainly located in the cell membrane and exhibits cell type- and stage-dependent functional differences during cancer development and inflammatory responses. However, the role of Lamprey-caveolin-like (L-caveolin-like) in lamprey remained unknown. Here, we demonstrated that L-caveolin-like performs anti-inflammation and oncogenic functions and the function of caveolin-1 diverged during vertebrate evolution. Moreover, the results reveal the mechanism underlying the antiapoptotic effects of L-caveolin-like. An L-caveolin-like gene from Lampetra japonica (L. japonica) was identified and characterized. L-Caveolin-like was primarily distributed in the leukocytes, intestines and supraneural bodies (Sp-bodies) immune organs as indicated by Q-PCR and immunohistochemistry assays. The mRNA and protein expression levels of L-caveolin exhibited consistent increases in expression at 2 and 72 h in adult tissues after exposure to lipopolysaccharide (LPS) and in leukocytes stimulated by Vibrio anguillarum (V. anguillarum), Staphylococcus aureus (S. aureus), and Poly I:C. Furthermore, the overexpression of pEGFP-N1-L-caveolin-like was associated with a distinct localization in mitochondria, with decreased cytochrome C (Cyt C) and mitochondrial Cyt C oxidase subunit I (CO I) expression. In addition, increased cellular ATP levels suggested that this protein prevented mitochondrial damage. The overexpression of pEGFP-N1-L-caveolin-like led to the altered expression of factors related to apoptosis, such as decreased Caspase-9, Caspase-3, p53, and Bax expression and increased Bcl-2 expression. In addition, the overexpression of pEGFP-N1-L-caveolin-like promoted cell proliferation associated with upregulated EGF, bFGF, and PDGFB expression. Together, these findings indicated that the L-caveolin-like protein from L. japonica induced the activation of antiapoptotic effects via the mitochondrial Cyt C-mediated Caspase-3 signaling pathway. Our analysis further suggests that L-caveolin-like is an oncogene protein product and anti-inflammatory molecule from lamprey that evolved early in vertebrate evolution.

Talin-1 interaction network promotes hepatocellular carcinoma progression

Talin-1 is a known oncogene-associated protein. In this study, we set out to determine its role and mechanisms in hepatocellular carcinoma (HCC) progression. We found Talin-1 to be highly expressed in HCC cells relative to non-cancer liver epithelial cells and to promote tumor growth and metastasis. We used Whole Human Genome Oligo Microarray analysis with HCC cells and HCC cells in which Talin-1 was knocked down using shRNA to identify transcripts regulated by Talin-1. Of the 40,000 tested genes, 3099 were differentially expressed after Talin-1 knockdown; expression of 1924 genes was increased, while expression of 2175 was decreased. Gene ontology (GO) profiling indicated that Talin-1 promotes many HCC progression-related activities, including ion transport and membrane depolarization, cell growth, and cell adhesion. We also characterized the network of gene transcripts regulated by Talin-1 and their role in promoting HCC progression. Our findings confirm the role of Talin-1 in carcinogenesis and provided a set of novel therapeutic targets for the treatment of HCC.

Enhanced expression of caveolin-1 possesses diagnostic and prognostic value and promotes cell migration, invasion and sunitinib resistance in the clear cell renal cell carcinoma

Caveolin-1 (CAV1) has been identified to be up-regulated in many cancers, including clear cell renal cell carcinoma (ccRCC). However, its potential function is still unclear in ccRCC. In this study, we demonstrated that CAV1 was frequently overexpressed in renal cell carcinoma tissues and cells, and was significantly associated with various clinicopathological parameters. In addition, high CAV1 expression was associated with poor disease-free survival (DFS) rate and could serve as a useful diagnostic indicator in ccRCC patients with different clinicopathological stages. Functional experiments demonstrated that CAV1 knockdown inhibited cell migration and invasion, whereas overexpression of CAV1 promoted cell migration and invasion in ccRCC. Moreover, CAV1 expression was up-regulated in sunitinib-resistant renal cancer cell lines, and its overexpression promoted sunitinib resistance. In general, our results confirm that CAV1 plays an important role in the metastasis of kidney cancer and induces sunitinib resistance, so CAV1 function suppression may become a promising clinical treatment strategy during renal cell carcinoma metastasis and sunitinib resistance.

Aberrant CpG Island Shore Region Methylation of CAV1 Is Associated with Tumor Progression and Poor Prognosis in Gastric Cardia Adenocarcinoma

BACKGROUND AND AIMS

Caveolin-1 (CAV1) is a multifunctional scaffolding protein and plays an important role in tumorigenesis. However, the epigenetic changes of CAV1 in gastric cardia adenocarcinoma (GCA) have not been investigated so far. The purpose of this study was to clarify the contribution of critical CpG sites in CAV1 to progression/prognosis of GCA and to further elucidate the effect of critical CpG sites on the ectopic expression of β-catenin in GCA.

METHODS

Methylation-specific polymerase chain reaction (MSP) and bisulfite genomic sequencing (BGS) methods were, respectively, applied to examine the methylation status of CAV1. RT-PCR and immunohistochemistry methods were used to determine the mRNA and protein expression of CAV1 and β-catenin.

RESULTS

Decreased mRNA and protein expression of CAV1 were observed in GCA tumor tissues and were associated with hypermethylation of CpG island shore and transcription start site (TSS) regions in CAV1. Hypermethylation of the other two regions within CpG islands in CAV1 was observed both in tumor and corresponding adjacent tissues but was not related to the transcriptional inhibition of CAV1. The methylation status of CpG island shore region in CAV1 was associated with the ectopic expression of β-catenin and was independently associated with survival in GCA patients.

CONCLUSIONS

Hypermethylation of CpG island shore and TSS regions is cancer specific and is closely associated with reduced expression of CAV1. The CpG island shore methylation of CAV1 may play an important role in progression of GCA and may serve as a prognostic methylation biomarker for GCA patients.

Dihydroartemisinin inhibits the viability of cervical cancer cells by upregulating caveolin 1 and mitochondrial carrier homolog 2: Involvement of p53 activation and NAD(P)H:quinone oxidoreductase 1 downregulation

Dihydroartemisinin (DHA) has been shown to inhibit the viability of various cancer cells. Previous studies have revealed that the mechanisms involved in the inhibitory effects of DHA are based on theactivation of p53 and the mitochondrial-related cell death pathway. However, the exact association between upstream signaling and the activation of cell death pathway remains unclear. In this study, we found that DHA treatment induced the upregulation of caveolin 1 (Cav1) and mitochondrial carrier homolog 2 (MTCH2) in HeLa cells, and this was associated with the DHA-induced inhibition of cell viability and DHA-induced apoptosis. Additionally, the overexpression of Cav1 and MTCH2 in HeLa cells enhanced the inhibitory effects of DHA on cell viability. Moreover, we also found that the upregulation of Cav1 contributed to the DHA-mediated p53 activation and the downregulation of the redox enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), which have been reported to contribute to the activation of the cell death pathway. Of note, we also found that DHA induced the nuclear translocation and accumulation of both Cav1 and p53, indicating a novel potential mechanism, namely the regulation of p53 activation by Cav1. On the whole, our study identified Cav1 and MTCH2 as the molecular targets of DHA and revealed a new link between the upstream Cav1/MTCH2 upregulation and the downstream activation of the cell death pathway involved in the DHA-mediated inhibition of cell viability.

Caveolin-1: An Oxidative Stress-Related Target for Cancer Prevention

Aberrant oxidative metabolism is one of the hallmarks of cancer. Reactive species overproduction could promote carcinogenesis via inducing genetic mutations and activating oncogenic pathways, and thus, antioxidant therapy was considered as an important strategy for cancer prevention and treatment. Caveolin-1 (Cav-1), a constituent protein of caveolae, has been shown to mediate tumorigenesis and progression through oxidative stress modulation recently. Reactive species could modulate the expression, degradation, posttranslational modifications, and membrane trafficking of Cav-1, while Cav-1-targeted treatments could scavenge the reactive species. More importantly, emerging evidences have indicated that multiple antioxidants could exert antitumor activities in cancer cells and protective activities in normal cells by modulating the Cav-1 pathway. Altogether, these findings indicate that Cav-1 may be a promising oxidative stress-related target for cancer antioxidant prevention. Elucidating the underlying interaction mechanisms between oxidative stress and Cav-1 is helpful for enhancing the preventive effects of antioxidants on cancer, for improving clinical outcomes of antioxidant-related therapeutics in cancer patients, and for developing Cav-1 targeted drugs. Herein, we summarize the available evidence of the roles of Cav-1 and oxidative stress in tumorigenesis and development and shed novel light on designing strategies for cancer prevention or treatment by utilizing the interaction mode between Cav-1 and oxidative stress.

Sclareol inhibits cell proliferation and sensitizes cells to the antiproliferative effect of bortezomib via upregulating the tumor suppressor caveolin-1 in cervical cancer cells

The anticancer effect of sclareol has long been reported, however, the exact mechanisms underlying the antitumorigenic effect of sclareol in cervical carcinoma remain to be fully elucidated. The present study analyzed cell proliferation and cell apoptosis by MTT and FITC-Annexin V assays. The protein levels of caveolin-1 (Cav-1) and copper-zinc superoxide dismutase (SOD)1 were determined by western blotting, and the interaction of Cav1 and HSC70 was investigated by co-immunoprecipitation experiments. The present study found that sclareol inhibited cell proliferation and induced apoptosis in HeLa cells. Two cancer-associated proteins, Cav1 and SOD1 were identified as potential targets of sclareol in HeLa cells. The expression of Cav1 increased when the cells were treated with sclareol, and the protein level of SOD1 was negatively correlated with Cav1. The overexpression of Cav1 enhanced the sensitivity of the HeLa cells to sclareol treatment and downregulated the protein level of SOD1, which exhibited potential associations between Cav1 and SOD1. In addition, sclareol significantly sensitized several cancer cells to the anticancer effect of bortezomib by targeting Cav1 and SOD1. Taken together, the results of the present study demonstrated that sclareol inhibited tumor cell growth through the upregulation of Cav1, and provides a potential therapeutic target for human cancer.

Global DNA methylation profiling uncovers distinct methylation patterns of protocadherin alpha4 in metastatic and non-metastatic rhabdomyosarcoma

Background

Rhabdomyosarcoma (RMS), which can be classified as embryonal RMS (ERMS) and alveolar RMS (ARMS), represents the most frequent soft tissue sarcoma in the pediatric population; the latter shows greater aggressiveness and metastatic potential with respect to the former. Epigenetic alterations in cancer include DNA methylation changes and histone modifications that influence overall gene expression patterns. Different tumor subtypes are characterized by distinct methylation signatures that could facilitate early disease detection and greater prognostic accuracy.

Methods

A genome-wide approach was used to examine methylation patterns associated with different prognoses, and DNA methylome analysis was carried out using the Agilent Human DNA Methylation platform. The results were validated using bisulfite sequencing and 5-aza-2′deoxycytidine treatment in RMS cell lines. Some in vitro functional studies were also performed to explore the involvement of a target gene in RMS tumor cells.

Results

In accordance with the Intergroup Rhabdomyosarcoma Study (IRS) grouping, study results showed that distinct methylation patterns distinguish RMS subgroups and that a cluster of protocadherin genes are hypermethylated in metastatic RMS. Among these, PCDHA4, whose expression was decreased by DNA methylation, emerged as a down-regulated gene in the metastatic samples. As PCDHA4-silenced cells have a significantly higher cell proliferation rate paralleled by higher cell invasiveness, PCDHA4 seems to behave as a tumor suppressor in metastatic RMS.

Conclusion

Study results demonstrated that DNA methylation patterns distinguish between metastatic and non-metastatic RMS and suggest that epigenetic regulation of specific genes could represent a novel therapeutic target that could enhance the efficiency of RMS treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2936-3) contains supplementary material, which is available to authorized users.

Effect of Repeat Dosing of Engineered Oncolytic Herpes Simplex Virus on Preclinical Models of Rhabdomyosarcoma

Rhabdomyosarcoma (RMS), a tumor of skeletal muscle origin, is the most common sarcoma of childhood. Despite multidrug chemotherapy regimens, surgical intervention, and radiation treatment, outcomes remain poor, especially in advanced disease, and novel therapies are needed for the treatment of these aggressive malignancies. Genetically engineered oncolytic viruses, such as herpes simplex virus-1 (HSV), are currently being explored as treatments for pediatric tumors. M002, an oncolytic HSV, has both copies of the γ₁34.5 gene deleted, enabling replication in tumor cells but thwarting infection of normal, postmitotic cells. We hypothesized that M002 would infect human RMS tumor cells and lead to decreased tumor cell survival in vitro and impede tumor growth in vivo. In the current study, we demonstrated that M002 could infect, replicate in, and decrease cell survival in both embryonal (ERMS) and alveolar rhabdomyosarcoma (ARMS) cells. Additionally, M002 reduced xenograft tumor growth and increased animal survival in both ARMS and ERMS. Most importantly, we showed for the first time that repeated dosing of oncolytic virus coupled with low-dose radiation provided improved tumor response in RMS. These findings provide support for the clinical investigation of oncolytic HSV in pediatric RMS.

Caveolin-1, a stress-related oncotarget, in drug resistance

Caveolin-1 (Cav-1) is both a tumor suppressor and an oncoprotein. Cav-1 overexpression was frequently confirmed in advanced cancer stages and positively associated with ABC transporters, cancer stem cell populations, aerobic glycolysis activity and autophagy. Cav-1 was tied to various stresses including radiotherapy, fluid shear and oxidative stresses and ultraviolet exposure, and interacted with stress signals such as AMP-activated protein kinase. Finally, a Cav-1 fluctuation model during cancer development is provided and Cav-1 is suggested to be a stress signal and cytoprotective. Loss of Cav-1 may increase susceptibility to oncogenic events. However, research to explore the underlying molecular network between Cav-1 and stress signals is warranted.

Rhabdomyosarcoma: Advances in Molecular and Cellular Biology

Rhabdomyosarcoma (RMS) is the most common soft tissue malignancy in childhood and adolescence. The two major histological subtypes of RMS are alveolar RMS, driven by the fusion protein PAX3-FKHR or PAX7-FKHR, and embryonic RMS, which is usually genetically heterogeneous. The prognosis of RMS has improved in the past several decades due to multidisciplinary care. However, in recent years, the treatment of patients with metastatic or refractory RMS has reached a plateau. Thus, to improve the survival rate of RMS patients and their overall well-being, further understanding of the molecular and cellular biology of RMS and identification of novel therapeutic targets are imperative. In this review, we describe the most recent discoveries in the molecular and cellular biology of RMS, including alterations in oncogenic pathways, miRNA (miR), in vivo models, stem cells, and important signal transduction cascades implicated in the development and progression of RMS. Furthermore, we discuss novel potential targeted therapies that may improve the current treatment of RMS.

The PARP inhibitor olaparib enhances the sensitivity of Ewing sarcoma to trabectedin

Recent preclinical evidence has suggested that Ewing Sarcoma (ES) bearing EWSR1-ETS fusions could be particularly sensitive to PARP inhibitors (PARPinh) in combination with DNA damage repair (DDR) agents. Trabectedin is an antitumoral agent that modulates EWSR1-FLI1 transcriptional functions, causing DNA damage. Interestingly, PARP1 is also a transcriptional regulator of EWSR1-FLI1, and PARPinh disrupts the DDR machinery. Thus, given the impact and apparent specificity of both agents with regard to the DNA damage/DDR system and EWSR1-FLI1 activity in ES, we decided to explore the activity of combining PARPinh and Trabectedin in in vitro and in vivo experiments. The combination of Olaparib and Trabectedin was found to be highly synergistic, inhibiting cell proliferation, inducing apoptosis, and the accumulation of G2/M. The drug combination also enhanced γH2AX intranuclear accumulation as a result of DNA damage induction, DNA fragmentation and global DDR deregulation, while EWSR1-FLI1 target expression remained unaffected. The effect of the drug combination was corroborated in a mouse xenograft model of ES and, more importantly, in two ES patient-derived xenograft (PDX) models in which the tumors showed complete regression. In conclusion, the combination of the two agents leads to a biologically significant deregulation of the DDR machinery that elicits relevant antitumor activity in preclinical models and might represent a promising therapeutic tool that should be further explored for translation to the clinical setting.

Non-caveolar caveolin-1 expression in prostate cancer cells promotes lymphangiogenesis

Lymphangiogenesis allows prostate cancer (PCa) lymphatic metastasis, which is associated with poor prognosis and short survival rates. Caveolin-1 (Cav-1) is a membrane protein localized in caveolae, but also exists in non-caveolar, cellular or extracellular forms. Cav-1 is overexpressed in PCa, promotes prostate tumour progression and metastasis. We investigated the effect of caveolar and non-caveolar Cav-1 on PCa lymphangiogenic potential. Cav-1 was down-regulated in PC3 and DU145, and ectopically expressed in LNCaP cells. The effect of PCa cell conditioned media on lymphatic endothelial cell (LEC) viability, chemotaxis, chemokinesis and differentiation was assessed. The effect of Cav-1 on PCa cell expression of lymphangiogenesis-modulators VEGF-A and VEGF-C was assessed using qPCR and ELISA of the conditioned medium. Non-caveolar Cav-1, whether exogenous or endogenous (in LNCaP and PC3 cells, respectively) enhanced LEC proliferation, migration and differentiation. In contrast, caveolar Cav-1 (in DU145 cells) did not significantly affect PCa cell lymphangiogenic potential. The effect of non-caveolar Cav-1 on LECs was mediated by increased expression of VEGF-A as demonstrated by neutralization by anti-VEGF-A antibody. This study unveils for the first time a crucial role for non-caveolar Cav-1 in modulating PCa cell expression of VEGF-A and subsequent LEC proliferation, migration and tube formation.

Novel POC1A mutation in primordial dwarfism reveals new insights for centriole biogenesis

POC1A encodes a WD repeat protein localizing to centrioles and spindle poles and is associated with short stature, onychodysplasia, facial dysmorphism and hypotrichosis (SOFT) syndrome. These main features are related to the defect in cell proliferation of chondrocytes in growth plate. In the current study, we aimed at identifying the molecular basis of two patients with primordial dwarfism (PD) in a single family through utilization of whole-exome sequencing. A novel homozygous p.T120A missense mutation was detected in POC1A in both patients, a known causative gene of SOFT syndrome, and confirmed using Sanger sequencing. To test the pathogenicity of the detected mutation, primary fibroblast cultures obtained from the patients and a control individual were used. For evaluating the global gene expression profile of cells carrying p.T120A mutation in POC1A, we performed the gene expression array and compared their expression profiles to those of control fibroblast cells. The gene expression array analysis showed that 4800 transcript probes were significantly deregulated in cells with p.T120A mutation in comparison to the control. GO term association results showed that deregulated genes are mostly involved in the extracellular matrix and cytoskeleton. Furthermore, the p.T120A missense mutation in POC1A caused the formation of abnormal mitotic spindle structure, including supernumerary centrosomes, and changes in POC1A were accompanied by alterations in another centrosome-associated WD repeat protein p80-katanin. As a result, we identified a novel mutation in POC1A of patients with PD and showed that this mutation causes the formation of multiple numbers of centrioles and multipolar spindles with abnormal chromosome arrangement.

DNA methylation dynamics in muscle development and disease

DNA methylation is an essential epigenetic modification for mammalian development and is crucial for the establishment and maintenance of cellular identity. Traditionally, DNA methylation has been considered as a permanent repressive epigenetic mark. However, the application of genome-wide approaches has allowed the analysis of DNA methylation in different genomic contexts revealing a more dynamic regulation than originally thought, since active DNA methylation and demethylation occur during cellular differentiation and tissue specification. Satellite cells are the primary stem cells in adult skeletal muscle and are responsible for postnatal muscle growth, hypertrophy, and muscle regeneration. This review outlines the published data regarding DNA methylation changes along the skeletal muscle program, in both physiological and pathological conditions, to better understand the epigenetic mechanisms that control myogenesis.